A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads, and/or other features etched from copper sheets laminated onto a non-conductive substrate. Components, such as capacitors, resistors, or other devices, are generally soldered onto the PCB. Advanced PCBs may contain components embedded in the substrate. A PCB may be single sided (e.g., having one copper layer), double sided (e.g., having two copper layers), or multi-layer (e.g., having outer and inner layers). Conductors on different layers are connected with vias. Multi-layer PCBs allow for much higher component density than single-layer PCBs.